Cross Sections

A cross-section is a
2
-dimensional “slice” of a
3
-dimensional figure. Another way to think of it is finding the
intersection
of a
2
-dimensional
plane
and a
3
-dimensional figure.

For any given
3
-dimensional figure, the cross-section depends on the orientation of the plane or “slice”.
For example, consider a
cylinder
. Various cross sections might result in a circle or rectangle, as shown below, or any of several other shapes.